There are many applications in which an increase in temperature indicates an abnormal condition requiring action. One example is when a current carrying conductor overheats due to excessive current, and the circuit must be broken in order to provide protection. Several techniques exist to overcome this situation, to which the present invention is an alternative.
Another example exists in the application of refrigeration to electronic equipment to provide improved performance. Since the reliability of refrigeration devices or cryo-coolers is inadequate to meet the stringent demands of electronic equipment availability, redundancy must be used wherein the failure of one cryo-cooler does not affect the thermal performance of the system. Typical redundancy for cryo-coolers requires using two coolers, each alone capable of satisfying the system thermal load, in intimate thermal contact with the load. If one cryo-cooler fails, the other must satisfy the load alone.
A problem that arises is that the failed cryo-cooler, in intimate thermal contact with the load, provides a thermal path draining the capacity of the functioning cryo-cooler, so dramatically affecting efficiency. In order to avoid this, a thermal switch is required between each cryo-cooler and the load. The switch must be an excellent thermal conductor when its associated cooler is operating correctly, but must become a thermal insulator when its associated cooler fails.
The object of the invention is to provide this switch capability, for which there are no known simple techniques currently available.